Death: Map

Wikipedia article:

Map showing all locations mentioned on Wikipedia article:

A human skull

A human skull

Death is the termination of the biological functions that define a livingorganism. It refers both
to a particular event and to the condition that results thereby.
The true nature of the latter has for millennia been a central
concern of the world's religious
traditions and of philosophical
enquiry. Belief in some kind of afterlife or rebirth
is a central aspect of most if not all religious traditions. The
contemporary scientificconsensus supposes death to terminate mind or consciousness. The
effect of physical death on any possible mind or soul remains for many an open question. Cognitive science has yet toexplain fully
the origin and nature of consciousness; any view about the existence or non-existence of consciousness after
death remains speculative.

Physiological death is now seen as less
an event than a process: conditions once considered indicative of
death are now reversible. Where in the process a dividing line is
drawn between life and death depends on factors beyond the presence
or absence of vital signs. In general,
clinical death is neither necessary
nor sufficient for a determination of legal
death. A patient with working heart and
lungs determined to be brain dead can be pronounced legally dead
without clinical death occurring. Precise medical definition of
death, in other words, becomes more problematic, paradoxically, as
scientific knowledge and technology advance.

Death in biology

Natural selection

Contemporary evolutionary theory sees
death as an important part of the process of natural selection. It is considered that
organisms less adapted to their
environment are more likely to die having produced fewer offspring,
thereby reducing their contribution to the gene pool. Their genes are thus eventually bred
out of a population, leading at worst to extinction and, more positively, making possible
the process referred to as speciation.
Frequency of reproduction
plays an equally important role in determining species survival: an
organism that dies young but leaves numerous offspring displays,
according to Darwinian criteria, much
greater fitness than a long-lived
organism leaving only one.

Extinction

Extinction is the cessation of existence of a species or group of
taxa, reducing biodiversity. The moment of extinction is
generally considered to be the death of the last individual of that
species (although the capacity to
breed and recover may have been lost before this point).
Because a species' potential range
may be very large, determining this moment is difficult, and is
usually done retrospectively. This difficulty leads to phenomena
such as Lazarus taxa, where a species
presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.
New species arise through the process of speciation, an aspect of evolution. New varieties of organisms arise and
thrive when they are able to find and exploit an ecological niche — and species become
extinct when they are no longer able to survive in changing
conditions or against superior competition.After death the remains
of an organism become part of the biogeochemical cycle. Animals may be
consumed by a predator or a scavenger.
Organic material may then be
further decomposed by detritivores,
organisms which recycle detritus, returning
it to the environment for reuse in the food
chain. Examples of detritivores include earthworms, woodlice and
dung beetles.

Microorganisms also play a vital role,
raising the temperature of the decomposing matter as they break it
down into yet simpler molecules. Not all materials need be
decomposed fully, however. Coal, a fossil fuel formed over vast tracts of time in
swamp ecosystems, is one example.

Evolution of aging

Enquiry into the evolution of aging aims to explain why so many
living things and the vast majority of animals weaken and die with
age (a notable exception being hydra,
which may be biologically
immortal). The evolutionary origin of senescence remains one of the fundamental puzzles
of biology. Gerontology specializes in
the science of human aging processes.

Defining death

Problems of definition

For those who define death as a state following the state of life,
one of the challenges in defining death is in distinguishing it
from life. Death would seem to refer to either
the moment at which life ends, or when the state that follows life
begins. However, determining when death has occurred requires
drawing precise conceptual boundaries between life and death. This
is problematic however because there is little consensus over how
to define life. Some have suggested defining life in terms of
consciousness. When consciousness ceases, a living organism can be
said to have died. One of the notable flaws in this approach is
that there are many organisms which are alive but probably not
conscious (for example, single-celled organisms). Another problem
with this approach is in defining consciousness, which remains a
mystery to modern scientists, psychologists and philosophers. This
general problem of defining death applies to the particular
challenge of defining death in the context of medicine.

Other definitions for death focus on the character of cessation of
something. In this context 'death' describes merely the state where
something has ceased, e.g., life. Thus, the definition of 'life'
simultaneously defines death.

Historically, attempts to define the exact moment of a human's
death have been problematic. Death was once defined as the
cessation of heartbeat (cardiac arrest) and of breathing, but the development of CPR and prompt defibrillation have rendered that definition
inadequate because breathing and heartbeat can sometimes be
restarted. Events which were causally
linked to death in the past no longer kill in all circumstances;
without a functioning heart or lungs, life can sometimes be
sustained with a combination of life
support devices, organ
transplants and artificial
pacemakers.

Today, where a definition of the moment of death is required,
doctors and coroners usually turn to "brain
death" or "biological death" to define a person as being
clinically dead; people are considered dead when the electrical
activity in their brain ceases. It is presumed that an end of
electrical activity indicates the end of consciousness. However, suspension of
consciousness must be permanent, and not transient, as occurs
during certain sleep
stages, and especially a coma. In the case of
sleep, EEGs can easily tell
the difference.

However, the category of "brain death" is seen by some scholars to
be problematic. For instance, Dr Franklin Miller, senior faculty
member at the Department of Bioethics, National Institutes of
Health, notes "By the late 1990s, however, the equation of brain
death with death of the human being was increasingly challenged by
scholars, based on evidence regarding the array of biological
functioning displayed by patients correctly diagnosed as having
this condition who were maintained on mechanical ventilation for
substantial periods of time. These patients maintained the ability
to sustain circulation and respiration, control temperature,
excrete wastes, heal wounds, fight infections and, most
dramatically, to gestate fetuses (in the case of pregnant
"brain-dead" women)."

The possession of brain activities, or ability to resume brain
activity, is a necessary condition to
legal personhood in the United States. "It appears that once
brain death has been determined … no criminal or civil liability
will result from disconnecting the life-support devices."
(Dority v. Superior Court of San Bernardino
County, 193 Cal.Rptr. 288, 291 (1983))

Many have challenged the idea that brain death is equivalent to the
cessation of consciousness. Critics point out that much of human
consciousness is embodied in numerous body parts and that the end
of electrical impulses in the brain does not necessarily indicate
that this embodied consciousness has also ceased. Given this
possibility, brain death does not necessitate the end of
consciousness, and thus brain dead people may still be alive.
Furthermore, some have argued, even if brain death does mean the
end of consciousness for a human being, the whole notion that
cessation of consciousness indicates death is problematic. Critics
note the existence of many single-celled organisms such as bacteria
that we consider to be alive but which many doubt are conscious. If
life does not require consciousness, defining death in terms of
"brain death" is a dubious procedure, even if the brain is the seat
of consciousness. Thus while legal concerns surrounding death force
us to develop a working definition of death, it is not at all clear
that the current American definition, according to brain death,
coincides at all with a definition that can be reasonably
endorsed.

Those people maintaining that only the neo-cortex of the brain is necessary for
consciousness sometimes argue that only electrical activity there
should be considered when defining death. Eventually it is possible
that the criterion for death will be the permanent and irreversible
loss of cognitive function, as evidenced
by the death of the cerebral cortex.
All hope of recovering human thought and personality is then gone given
current and foreseeable medical technology. However, at present,
in most places the more conservative definition of death —
irreversible cessation of electrical activity in the whole brain,
as opposed to just in the neo-cortex — has been adopted (for
example the Uniform
Determination Of Death Act in the United States). In 2005, the Terri Schiavo case brought the question
of brain death and artificial sustenance to the front of American politics.

Even by whole-brain criteria, the determination of brain death can
be complicated. EEGs can detect spurious electrical impulses, while
certain drugs, hypoglycemia, hypoxia, or hypothermia can suppress or even stop brain
activity on a temporary basis. Because of this, hospitals have
protocols for determining brain death involving EEGs at widely
separated intervals under defined conditions.

Misdiagnosed death

There are many anecdotal references to people being declared dead
by physicians and then 'coming back to life', sometimes days later
in their own coffin, or when embalming
procedures are just about to begin. Owing to significant scientific
advancements in the Victorian era,
some people in Britain became
obsessively worried about living after being declared
dead.

As medical technologies advance, ideas about when death occurs may
have to be re-evaluated in light of the ability to restore a person
to vitality after longer periods of apparent death (as happened
when CPR and defibrillation showed that
cessation of heartbeat is inadequate as a decisive indicator of
death). The lack of electrical brain activity may not be enough to
consider someone scientifically dead. Therefore, the concept of
information theoretical
death has been suggested as a better means of defining when
true death actually occurs, though the concept has few practical
applications outside of the field of cryonics.

There have been some scientific attempts to bring dead organisms
back to life, but with limited success. In science fictionscenarios where such technology is readily
available, real death is distinguished
from reversible death.

Death and the law

In the United States, a person is dead by law if a Statement of
Death or Death Certificate is
approved by a licensed medical practitioner. Various legal
consequences follow death, including the removal from the person of
what in legal terminology is called personhood.

According to Jean Ziegler, who was the
United Nations Special reporter on
the Right to Food from 2000 to March 2008; mortality due to
malnutrition accounted for 58% of the
total mortality rate in 2006. Ziegler says worldwide approximately
62 million people died from all causes and of those deaths more
than 36 million died of hunger or diseases due to deficiencies in
micronutrients."

Tobacco smoking killed 100 million people
worldwide in the 20th century and could kill 1 billion people
around the world in the 21st century, a
WHO Report warned.

Many leading developed world causes of death can be postponed by
diet and physical activity, but the accelerating
incidence of disease with age still imposes limits on human
longevity. The evolutionary cause of aging is, at best,
only just beginning to be understood. It has been suggested that
direct intervention in the aging process may now be the most
effective intervention against major causes of death.

Signs of death

Signs of death, or strong indications that a person is no longer
alive are:

Ceasing respiration

The body no longer metabolises

Pallor mortis, paleness which
happens in the 15–120 minutes after the death

Livor mortis, a settling of the
blood in the lower (dependent) portion of the body

Algor mortis, the reduction in body
temperature following death. This is generally a steady decline
until matching ambient temperature

Rigor mortis, the limbs of the
corpse become stiff (Latin rigor) and difficult to move or
manipulate

Autopsies are either performed for legal or medical purposes. A
forensic autopsy is carried out when the cause of death may be a
criminal matter, while a clinical or academic autopsy is performed
to find the medical cause of death and is used in cases of unknown
or uncertain death, or for research purposes. Autopsies can be
further classified into cases where external examination suffices,
and those where the body is dissected and an internal examination
is conducted. Permission from next of
kin may be required for internal autopsy in some cases. Once an
internal autopsy is complete the body is generally reconstituted by
sewing it back together. Autopsy is important in a medical
environment and may shed light on mistakes and help improve
practices.

A "necropsy" is an older term for a postmortem examination,
unregulated, and not always a medical procedure. In modern times
the term is more often used in the postmortem examination of the
corpses of animals.

Researchers of life extension are a subclass of biogerontologists known as "biomedical gerontologists". They try to understand the
nature of aging and they develop treatments to reverse aging
processes or to at least slow them down, for the improvement of
health and the maintenance of youthful vigor at every stage of
life. Those who take advantage of life extension findings and seek
to apply them upon themselves are called "life extensionists" or
"longevists". The primary life extension strategy currently is to
apply available anti-aging methods in the hope of living long
enough to benefit from a complete cure to aging once it is
developed, which given the rapidly advancing state of biogenetic
and general medical technology, could conceivably occur within the
lifetimes of people living today.

Death in culture

Death is the center of many traditions and organizations, and is a
feature of every culture around the world. Much of this revolves
around the care of the dead, as well as the afterlife and the disposal of bodies upon the
onset of death. The disposal
of human corpses does, in general, begin with the last offices before significant time has
passed, and ritualistic ceremonies often occur, most commonly
interment or cremation. This is not a
unified practice, however, as in Tibet for
instance the body is given a sky burial
and left on a mountain top. Proper preparation for death and
techniques and ceremonies for producing the ability to transfer
one's spiritual attainments into another body (reincarnation) are subjects of detailed study
in Tibet. Mummification or embalming is also prevalent in some cultures, to
retard the rate of decay.

Suicide in general, and particularly
euthanasia are also points of cultural
debate. Both acts are understood very differently in contrasting
cultures. In Japan, for
example, ending a life with honor by seppuku
was considered a desirable death, whereas according to traditional
Christian and Islamic cultures, suicide is viewed as a sin.
Death is personified in many
cultures, with such symbolic representations as the Grim Reaper, Azrael and
Father Time.